Jenny Green, public affairs specialist with NMDA, talks with KC Counts about equine herpes virus and what horse owners need to know. Here is a transcript of their conversation:
KC Counts:
I'd like you to talk about the decision to close the county barns due to the outbreak of this equine virus. What went into that decision?
Jenny Green:
So right now, barns in general, areas that are close to effective cases, are really heightening their biosecurity. So I would have to say that closure took place just as a precaution so that the virus isn't spread. It's very contagious to other horses. So they don't want traffic coming in or going out at this time.
KC Counts:
We just recently heard of the outbreak from a barrel racing event in Waco, Texas, right? And now there's already a case been identified in New Mexico. Do we know if they're linked?
Jenny Green:
Yeah, so to give you kind of a quick update on the situation in New Mexico, there are three confirmed cases at this time, one in Doña Ana County and two in Eddy County. And all of those cases can be traced back to the WPRA event in Waco, which took place early this month in November. And those cases are all responding to supportive veterinary care. One horse in Eddy County did attend that event, and the horse in Doña Ana County attended that event as well. A second horse in Eddy County got the virus from the horse that attended the event. Unfortunately, those horses were on the same property, so that virus was transmitted pretty easily.
KC Counts:
What is it that people need to be watching for?
Jenny Green:
So really, we're stressing that people watch for signs and symptoms of respiratory illness. So myeloencephalopathy is the neurologic form of the virus, and that's really a manifestation of the equine herpes virus. So watch for fever, nasal discharge, cough, lethargy; in severe cases, the horse might be unable to stand, and practice strict biosecurity practices. So don't share halters, buckets, tack, grooming tools, and pay attention to disinfecting practices and stalls and barns as well as trailers. And horses, whether they're new to a property, or have returned to a property from an event or from elsewhere, they should be isolated for two to three weeks.
KC Counts:
What's the prognosis like for horses that do become infected?
Jenny Green:
So, the prognosis for equine herpes virus is pretty good with supportive care. It's really the more severe neurological symptoms that we have to worry about. Those horses may not recover. Mares usually recover with supportive care in respiratory cases. If it's neurologic, early intervention improves outcomes.
KC Counts:
What else is important for people to know about this disease and how to stay safe?
Jenny Green:
Sure, so one of the most important things that we're stressing right now is that the spread of it is preventable. Immediate isolation and early veterinary evaluation are the best tools we have right now. If horse owners have questions about equine herpes virus testing, they can reach out to NMDA's Veterinary Diagnostic Services. And if they have regulatory or livestock concerns, they can reach out to the New Mexico Livestock Board. And you might also want to keep an eye on the New Mexico Livestock Board website. If you check out their “What's New” web page, they have a county map there showing the latest quarantines and hold orders due to EHV. And you can also, if you scroll down a little bit on that page, you can find the most up-to-date state entry requirements that were posted on November 21st. And those indicate that effective immediately, horses entering New Mexico from states with confirmed EHV cases must be issued a certificate of veterinarian inspection within five days of travel.
KC Counts:
Good to know.
Jenny Green:
There are resources out there for folks.
KC Counts:
All right. Well, thank you very much for sharing this important information with us. We
appreciate your time, Jenny.
Jenny Green:
Yeah, no problem at all.
Here is a fact sheet from the New Mexico Department of Agriculture with links to resources:
Equine Herpesvirus-1 (EHV-1) Fact Sheet
Updated 11/20/25
Overview
Equine Herpesvirus-1 (EHV-1) is a common, highly contagious virus affecting horses, donkeys and mules. It spreads through respiratory secretions, shared equipment, trailers and contaminated environments. EHV-1 can cause respiratory disease, abortions, foal death and a serious neurologic condition known as Equine Herpes Myeloencephalopathy (EHM). EHV-1 does not infect humans. The incubation period for EHV-1 is typically 2-10 days, and can become dormant, reactivating later.
Clinical signs of EHV-1 include:
Fever, nasal discharge, cough, lethargy, swollen lymph nodes, weak or stillborn foals, hindlimb weakness or incoordination, difficulty rising, loss of tail tone, urinary retention, recumbency (unable to stand)
Diagnosis:
Veterinarians diagnose EHV-1 primarily through PCR testing of nasal swabs and whole blood. PCR is the most accurate method. Early testing and immediate isolation are essential to limiting virus spread.
Treatment:
There is no cure, but consult your veterinarian about options for supportive care. All infected horses must be strictly isolated to help prevent the spread of the virus.
Prognosis:
Respiratory cases: Typically recover fully.
Reproductive cases: Mares usually recover; foals rarely survive.
Neurologic cases: Highly variable. Mild cases may improve; severe paralysis often carries a poor prognosis.
Prevention:
Vaccinate according to veterinary recommendations. Isolate new horses for 2-3 weeks before introducing them to the herd. Avoid sharing halters, water buckets, grooming tools, tack, etc. Disinfect barns and equipment regularly. Monitor temperatures daily during high-risk periods. Limit horse movement during regional or local outbreaks. Immediate isolation and veterinary evaluation of any suspected case are critical.
Contacts:
New Mexico Livestock Board: 505-841-6161. • Call New Mexico Department of Agriculture’s Veterinary Diagnostic Services for questions about EHV-1 testing: 505-383-9299. • Call your local veterinarian for questions about diagnosis, treatment and vaccination.
Resources:
New Mexico Department of Agriculture:
https://nmdeptag.nmsu.edu/#gsc.tab=0
New Mexico Livestock Board:
https://www.nmlbonline.com/search.php
